Purpose: Glioblastoma is the most malignant primary brain tumor, with a median survival of less than 2 years. More effective therapeutic approaches are needed to improve clinical outcomes.
Experimental Design: Glioblastoma patient-derived cells (GPDC) were isolated from patient glioblastomas and implanted in mice to form xenografts. IHC was performed for human Ether-à-go-go-Related Gene (hERG) expression and tumor proliferation. Sphere-forming assays with the hERG blocker E-4031 were performed on a high and low hERG–expressing lines. A glioblastoma tissue microarray (TMA; 115 patients) was used to correlate hERG expression with patient survival. Clinical data were analyzed to determine whether patient survival was affected by incidental administration of hERG inhibitory drugs and the correlative effect of patient glioblastoma hERG expression levels.
Results: hERG expression was upregulated in glioblastoma xenografts with higher proliferative indices. High hERG–expressing GPDCs showed a reduction in sphere formation when treated with hERG inhibitors compared with low hERG–expressing GPDCs. Glioblastoma TMA analysis showed worse survival for glioblastoma patients with high hERG expression versus low expression—43.5 weeks versus 60.9 weeks, respectively (P = 0.022). Furthermore, patients who received at least one hERG blocker had a better survival rate compared with patients who did not (P = 0.0015). Subgroup analysis showed that glioblastoma patients with high hERG expression who received hERG blockers had improved survival (P = 0.0458). There was no difference in survival for low hERG–expressing glioblastoma patients who received hERG blockers (P = 0.4136).
Conclusions: Our findings suggest that hERG is a potential glioblastoma survival marker, and that already approved drugs with non-torsadogenic hERG inhibitory activity may potentially be repurposed as adjuvant glioblastoma therapy in high hERG–expressing glioblastoma patients. Clin Cancer Res; 23(1); 73–80. ©2016 AACR.
See related commentary by Arcangeli and Becchetti, p. 3
This article is featured in Highlights of This Issue, p. 1
Note: Supplementary data for this article are available at Clinical Cancer Research Online (http://clincancerres.aacrjournals.org/).
- Received January 14, 2016.
- Revision received August 12, 2016.
- Accepted September 3, 2016.
- ©2016 American Association for Cancer Research.